According to english grammer rules in past tense & In negative and interrogative sentences 2nd form of the verb changes to 1st form so:

1) Did u buy this one? (Correct)2) Did u go to disneyland yet? ( It is used when someone was on his way to somewhere like here disneyland) Have u been to disneland is used when u want someone to ask if he has ever gone to somewhere, even he may have returned.

For movies we use watch instead of see. &The last one:Did u go for shopping? (Correct)